This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: How long did it take for oxygen to build up in the Earth's atmosphere to its present levels? A) ... (Read 66 times)

809779

  • Hero Member
  • *****
  • Posts: 579
on: Jul 27, 2018
How long did it take for oxygen to build up in the Earth's atmosphere to its present levels?
 
  A) at least 542 million years
  B) at least 360 million years
  C) at least 2 billion years
  D) at least 3.5 billion years

Question 2

Express the following number to three significant figures: 21.25 m
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

blakeserpa

  • Sr. Member
  • ****
  • Posts: 338
Reply #1 on: Jul 27, 2018
Answer to Question 1

C

Answer to Question 2

21.3 m


809779

  • Member
  • Posts: 579
Reply 2 on: Jul 27, 2018
YES! Correct, THANKS for helping me on my review

diana chang

  • Member
  • Posts: 288
Reply 3 on: Yesterday
Gracias!

« previous next »
 

Did you know?

There are actually 60 minerals, 16 vitamins, 12 essential amino acids, and three essential fatty acids that your body needs every day.

Did you know?

Methicillin-resistant Staphylococcus aureus or MRSA was discovered in 1961 in the United Kingdom. It if often referred to as a superbug. MRSA infections cause more deaths in the United States every year than AIDS.

Methicilli ...
Did you know?

Aspirin may benefit 11 different cancers, including those of the colon, pancreas, lungs, prostate, breasts, and leukemia.

Did you know?

In women, pharmacodynamic differences include increased sensitivity to (and increased effectiveness of) beta-blockers, opioids, selective serotonin reuptake inhibitors, and typical antipsychotics.

Did you know?

The U.S. Preventive Services Task Force recommends that all women age 65 years of age or older should be screened with bone densitometry.

Titan's dense atmosphere shrouds the moon beneath a tan haze in this image. Titan's dense atmosphere shrouds the moon beneath a tan haze in this image.
The Sun as it appears from the surface of Earth before sunset. The Sun as it appears from the surface of Earth before sunset.
Tides on Earth Tides on Earth
How Orbital Eccentricity Changes the Amount of Solar Radiation Earth Receives How Orbital Eccentricity Changes the Amount of Solar Radiation Earth Receives
Hormones acting through the brain help regulate metabolism and short- and long-term appetite. Hormones acting through the brain help regulate metabolism and short- and long-term appetite.
Humoral control of blood sugar levels. Humoral control of blood sugar levels.
Video: How proteins function? How do proteins work?

For a complete list of videos, visit our video library